Nasalstops such as [m] can only be pronounced at buccal POAs. Phonation contrasts, while some are possible even for guttural consonants, are also typically limited to buccal consonants.

Debuccalization refers to the change from a buccal consonant to a glottal. Typically stops will end up as [ʔ], fricatives as [h], though there is room for variation (eg. *ɟʱ, *gʱ → [ɦ] in Sanskrit). The opposite change is buccalization; typically the result will be a velar (eg. *ʔ → k, *h → x). (The term glottalization is usually only applied to changes resulting in [ʔ] or glottalized consonants.)